Extraction and characterization of bioactive compounds from coffee by-products: physicochemical and LC-MS analysis

Spent coffee grounds (SCGs), an abundant byproduct of Coffea arabica L., hold significant potential as a renewable resource for bioactive compounds. This study explores ultrasound-assisted extraction (UAE) as a sustainable approach to enhance the recovery of phenolic-rich metabolites using seven solvents with varying polarity. The optimized glycerol/methanol co-solvent system achieved the highest extraction efficiency, with a total phenolic content (TPC) of 6.059 ± 0.089 mg GAE/g and a total flavonoid content (TFC) of 8.549 ± 0.010 mg QE/g. Comprehensive liquid chromatography − mass spectrometry (LC-MS) analysis identified key secondary metabolites, including caffeine, chlorogenic acids (CGAs), and phenolic compounds which contribute to diverse functional properties such as antioxidant, antimicrobial, UV-protective, anti-inflammatory, and anti-cellulite activities. These bioactive components have substantial applications in industrial crop-based pharmaceuticals, cosmetics, and bio-based materials. By integrating UAE with environmentally friendly co-solvents, this study presents a scalable and sustainable extraction strategy, reducing reliance on conventional solvents while maximizing yield and purity. Additionally, the findings support waste valorization and circular economy principles, positioning SCGs as a viable industrial crop resource with significant implications for biorefinery processes, bio-based product development, and sustainable cropping systems. This research provides a systematic framework for solvent selection in metabolite extraction, reinforcing its relevance to industrial crop management and sustainable bioactive compound production. The demonstrated efficacy of UAE establishes SCGs as an untapped industrial crop derivative, contributing to the advancement of green extraction technologies and industrial applications.